Comments on "A Novel Planar Switched Parasitic Array Antenna With Steered Conical Pattern

A number of problems with p.i.n. diode switching circuits have been identified which might affect the Chen et al. results. A number of design requirements must be met to obtain ideal antenna performance. If switch activation symmetry is maintained, the centre frequency should not change. If a change in centre frequency is observed experimentally, then the cause might lie in imperfections inthe switching network. Note also that if beam elevation is to be controlled, a conducting skirt can be added to the ground plane.